This disclosure relates to power circuits in general and, in particular, to switching converter circuits.
Many electronics applications use switching power converters to convert a DC bus voltage to an appropriate load voltage. For example, a load may desire conversion of mains line voltage to 12-volt DC voltage. A first conversion stage may convert the high-voltage AC mains line voltage to a high-voltage DC bus voltage (e.g., while also providing power factor correction). A second stage may then convert the high-voltage DC bus voltage to the appropriate low-voltage DC load voltage, as desired.
In many applications, the second stage converter may be a switching converter that generates a desired output level by switching at a particular duty cycle. While the converter may adjust its duty cycle to maintain a desired output level, the efficiency of the converter may change over a certain range of duty cycles. For example, the efficiency may increase as the duty cycle approaches 100 percent. As such, some typical switching converters may be limited in their ability to adapt to changing output conditions while maintaining high efficiency.